Rosemarie Dewitt on Her Toronto Sex Comedy Your Sister’s Sister

Yesterday at the Toronto Film Festival, Lynn Shelton’s sibling-mayhem sex comedy, Your Sister’s Sister, scored a distribution deal with IFC Films. The follow-up to Humpday, the film stars Mark Duplass as Jack, a guy who ends up in bed with Hannah, his best friend Iris’s lesbian sister, who is played with marvelously dry, unimpressed charm by Rosemarie Dewitt. Turns out the best friend, played by Emily Blunt, is madly in love with him, and Hannah is holding a huge secret. Vulture spoke to Dewitt (United States of Tara, Mad Men, Cinderella Man) about improvising comedy and Mark Duplass’s long, rambling monologue in praise of her butt.

So, originally, Rachel Weisz was cast for your role?
Rachel had a scheduling conflict, so I got a call from her on a Saturday morning saying, “Please, please say yes — it’s an amazing group.” I was in the middle of shooting United States of Tara and thought, Unless it shoots on the Paramount lot, I’m not going to be able to do this. But I’d flipped out over Humpday, so when I found out what it was, I made all these begging calls to my bosses at Tara saying, “Please, please help me work with this."

So they accommodated your schedule?
I got the job on a Saturday. On Tuesday, I shot half a day of Tara, got on a plane, and went up and shot the tequila scene, sex scene, and got back the next day. I was a commuter, going back and forth [from Washington] to L.A. But Hannah [her character] was a mess, so it didn’t matter if I hadn’t slept and looked like hell. Everything fit.

You get very drunk. Was that real tequila?
A shot or two. But I remember thinking, God, that was a missed opportunity. We could have been chugging tequila. But it’s hard; you have to be lucid to keep in mind the bigger story going on within the little story improv.

You’ve done theater and TV and film, but have you ever improvised this much before?
Nothing to this degree. I definitely like it in films, but there was a little overload because you’re a writer and an actor at the same time, where you have to hold the whole story in your head always. It’s one thing to go off script, it’s another to say, “We need to get these six things into this scene and — Oh, shit! I forgot that one and how do we get it back in there?” Mark and Lynn have worked a lot like this, but Emily and I were walking around sometimes asking each other, “Is this making any sense?”

Mark Duplass delivers a long monologue about the wonder of your ass.
You know, in improvised movies, 80 percent ends up on the cutting-room floor, so Lynn could have latched onto anything. You’re like, “Really, Lynn, you’re going with a five-minute conversation about her ass?”

And your sex scene with Duplass is just terrible.
While working on this I was going back and forth to Tara, and I asked a good friend who was a lesbian, "Would you ever do that, get out of a long-term relationship with a woman and sleep with a guy? Just for a one-night stand?" She said, “No, because inevitably the next morning you wake up with a dick in your back.” I knew Hannah would regret it.

Shelton has said that she likes taking these very absurd premises and then executing them in a very real way. Did you talk about how to do that on set?
It was kind of a non-issue on set. Her way of working and her sensibilities are insanely grounded. I’d described that premise to friends, they’d say that sounds ridiculous, but the world of it is so real and so grounded. Humpday was even more out there in terms of the premise, and hit on things I hadn’t really seen before in terms of male friendship and identity.

I was so surprised that Humpday was so moving.
I went with a girlfriend and two guy friends. The guys were so undone by it. Lynn had her finger on the pulse of something that connected with them. They kept saying, "That’s the struggle, you guys: You’re either the guy in the world or the guy who settles down." They’re the issues everyone has and mostly you just sit on them. She unravels them.

This becomes another film about an alternative way to raise a child. There are all these new configurations out there in movies now, aren’t there?
It’s really fertile ground: The what-ifs are so much more expansive now, and you see it in all your neighbors. I applaud Lynn for taking this out of the real of what was possible. You know, if people’s desires were big enough, there’s this potentially interesting family unit [in the film]. When you get down into the nitty-gritty of it, there are all sorts of ways to start a family: We have these friends, two gay men who adopted twins who are not the same race as the parents with no mom in the picture. One day, the kids said, “We’re adopted? Are you kidding!” Sometimes, you think the kids are game for anything and that it’s grown-ups that project all these things.

And, sorry, I have to ask: What do you think happened to Midge on Mad Men? I wish she could come back.
I don’t know if she’d ever come back. I just hope she didn’t meet a tragic ending after that last episode. Her situation was pretty grim. But I still hope she gets her show at the Whitney and never goes back into Don Draper’s world.

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